Specific radio frequency bands are set aside for wireless cellular communications by spectrum regulatory authorities (such as the Federal Communications Commission in the United States of America) to ensure the reliable operation of cellular communication systems, and are referred to as cellular bands. The term ‘spectrum’ is commonly used to refer to the aggregate bands that are assigned to the cellular communication network, also referred to as the cellular communication system, in any given jurisdiction. Another analogous phrase to spectrum is radio frequency resources.
Cellular bands can be contiguous or non-contiguous and are typically divided into sub-bands, which again can be contiguous or non-contiguous, that are licensed to mobile network operators. A mobile network operator thus deploys the network infrastructure of a cellular communication system, comprising a Radio Access Network (RAN) and a Core Network (CN), upon obtaining a spectrum utilization license, i.e. a license to use a particular cellular band or sub-band. The RAN connects User Equipment (UE) to the CN, where cellular communication systems are interconnected with other communication systems.
A RAN typically comprises processing units and equipment (such as antennas, circuits, connecting cables, etc.) that perform Radio Transmission Functions (RTFs) in addition to other functions, referred to as non-Radio Transmission Functions (non-RTFs).